The present invention relates to heat-exchangers of the plate fin type, for example, for use in oil coolers and the like.
The term "aluminum" as herein used includes aluminum and aluminum alloys.
Conventional oil coolers made, for example, of aluminum have first flow channels for passing an oil therethrough and second flow channels for passing air therethrough in a direction intersecting the first channels at right angles therewith, the first and second channels being arranged alternately one above the other as separated by a flat plate. Each of these flow channels is formed by a pair of flat plates disposed in parallel with each other at a specified spacing, spacer bars provided between the flat plates and serving as opposite side walls, and corrugated fins arranged between the spacer bars. The spacer bars and the corrugated fins are joined together, for example, by vacuum brazing, as held between the flat plates each comprising an aluminum brazing sheet. However, the conventional oil cooler is composed of a large number of parts, therefore requires much time for setting the parts, is not easily settable automatically, is inefficient to fabricate and is heavy.
The conventional oil cooler has fins such as multientry fins (offset fins) within the oil passing first flow channels. The conventional fins, which have projections at a small spacing, afford a relatively large amount of heat exchange to achieve a high efficiency, whereas they result in a very great pressure loss, consequently requiring an increased pump output pressure to maintain the desired oil pressure and entailing a corresponding increase in equipment cost as well as in power cost. The pressure loss may be diminished by increasing the spacing between the fin projections, but a reduced heat exchange efficiency will then result.